Method of and apparatus for spinning



Dec. 5, 1933. w. WHITEHEAD METHOD OF AND APPARATUS FOR SPINNING Filed Jan. 21, 1929 INVENTOR William Whi're hgead ATTORNEYS atented Dec. 5, 1933 I V I v I UNITED j stares PA ENT; OFFICE s in 1,937,614 i i METHOD 'oF AND APPARATUS FOB. v7 SPINNING g 2 William Whitehead, Cumberland, Mill, assignor to Celanese Corporation of America, a. corporation of Delaware Application January 21, 1929. Serial No; 333,843

4 Claims. I (Cl. 188) This invention relates to method of and appatemperatures are lower, the physical strengthof ratus for the manufacture of artificial filaments, theyarns produced issOm'evvhat lower, and the such as yarns, bristles and the like, and relates actual drying ofthe filamentsor yarns-is poor.

' more particularly to those methods wherein a Therefore, if these temperaturesvary duringjthe 5 solution of a derivative of cellulose in a volatile spinning process, filam'ents'or yarns of varying 60 solvent is extruded through orifices into a heated lustre, strength and other optical or} phySical evaporative atmosphere, which methods are properties areprodu'ced. J i known as dry spinning methods. In the method'formerly employed, thespinnihg An object of my invention is to obtain artificial solution in the jet or spinneret is heated tosome 10 filaments'or yarns containing organic derivatives extent by the heated drying atmosphere that'fiows 65 of cellulose that have more uniform lustre and by it. .f-'iowe' .-er, this heating is not uniform, due other optical and physical properties than those to the fact that the convection currents "in the previously'made. A further object of my in-- spinning cabinet vary andthus causedifferent vention is to provide a process of apparatus temperatures arounclthe jet and aroundthe filafor the dry spinning of artificial filaments from nients under'form'ation. This non-uniforrn'heat- 70' solutions of derivatives of cellulose in volatile ing also due to the fact that the drafts o'r dif solvents, whereby the solution of the derivative ierences in temperatures "outside the foabinet of cellulose is heated near the temperature at cause the spinning .solutions to have different which it is in equilibrium with the evaporative temperaturesjprior to theirentryinto the spinatmosphere prior to extrusion through the orining cahin'et,'-and the amountof heat'supplied' to 75 fices of the jet or spinneret. 1 the spinning solution While in'thecaloinet'prior to [A further object of my invention is to protheextrusion through the orifices'of the spinneret vide a process of and apparatus for the dry by heat exchange withthe heated evaporative'a't spinning of artificialjfilaments from solutions of mosphere, is notsufiiciently-great to-impart 'uniderivatives of cellulose in volatile solvents'whereform temperatures to the-spinning 5011mm; so

in the temperature of the solution is maintained I have found that if the spinningsolution is substantially uniform prior to extrusion through positively heated by a suitable mediumfto "a unithe orifices of a 'jet or spinneret. Othe objects form temperatura w hich temperaturef'is 'pre'fl of my invention will appear from the following erably .near the temperature of the evaporativedetailed description. I atmosphere in the'vicinity of the mouth of the '35 I In a method heretofore em' loyed for the dry spinning jet, justpr'ior toextrusion throughthe spinning of artificial yarn from a solution of orifices of 'the jet,'filaments or yarns of uniform derivatives of celluloseand volatile solvents, such lustre, strength, cross section and other optical solution is forced by a pump, which is outside randphysical properties may be produced.

a spinning cabinet, into a spinning unit whieh In accordancefvvith myinveritionIprepare rticomprises a spinning jet andsometimes afilter, ficial filamentsfrom solutions of organicd which jet and filter are situated Within the cabitives of cellulose in a suita le volatile solve net-through which a heated evaporative gas fiows. passing the same'through chambers or othe' de- 'I-he filaments formed are passed through the vices where they are positively heatedhy 'a'sufit- 40 evaporative atmosphere Where the volatile solable heating medium of uniform temperature, 95

vent evaporates, and the dry filamentsare wound wherein the temperature of the 'spinningjsolu on atextile machine tionis raised to a point that is near the boiling I 'The'p'rior method does not produce yarns of point of the voiatile solvent,just priorlto their perfectly uniform lustre, or uniform other optical extrusion through the orificesv or a spinni jet 1 V H or physical characteristics. I have found that into avheated evaporativeatmosphere; j Thefila 100 this is due, among other factors, to the fact that ments or yarns thus'formedare then 'Idravvn off the solution of derivatives of cellulose is not at and wound'onto 'a Winding machine running at a. sufiiciently elevated temperature and is not of uniform rate which winding' m'a'chine 'inay ,also uniform temperatures just prior to its leaving the imparttwistlto the filament, if desiredl Thefilaorifices of the spinning jet. I have found that ments'or yarns thusi'formediarepf a high and' r05v in order to obtain lustrous filaments or yarns, uniform lustre and have other desirable uniform v elevatedtemperatures of the evaporative medium optical and physical properties;

. andof jthe'spinning solutions are necessary, and Any suitable artificial filaments'or yarnsmay! j 'the 're'ductio'n of such temperatures lowers the be produced by my invention, The filaments may lustreof theyarn'slproduced. Further, if these hefine, say, having deniers of leissithan'z 1310 p I fror brushes or artificial fur. may also be made by my invention to be-used in or more, to be used as such, or to be associated together to form yarns of Various size.

filaments having deniers of 20 to 500 or more Heavier may alsobe made to be used as artificial bristles Bands or ribbons making braids or as artificial straw. 'Any suitable organic derivative of cellulosemay be, employed such as organic esters of cellulose ate, cellulose propionate and cellulose butyrate, while examples of cellulose ethers are ethyl celluand cellulose ethers.

of cellulose are cellulose acetate, cellulose formlose, methyl cellulose and benzyl cellulose. So-

lutions of celulose nitrate may also be spun in this manner, and if desired the cellulose nitrate filaments or yarns may then'be denitratedin any suitable manner.

Any suitable solvent may be employed examples of which are acetone, mixtures of chloroform and ethyl alcohol or methyl alcohol, ethylene dichloride, methylene chloride and alcohol, or other suitable solvents or suitable mixtures of these,

to which may be added suitable diluentsiir" desuch chambers, althoughunder some circum- (Ill stances iti's desirable that all of these parts be heated. Where solvents of comparatively high boiling points are employed, I prefer not to heat the pump too high for obvious reasons' Theheating medium employed for heating the devicescontaining the spinning solution should produce uniform temperature and may be of any suitable character. I prefer to employ as a heatingmedium liquids of high boiling points and reasonably low vapor pressure in order to avoid evaporation losses. Such liquids should preferably also have a high specific heat so that upon the, loss of a given number of calories, little drop of temperature is experienced. In order to avoid convection currents, the liquid should preferably be of high viscosity. An example of a liquid that combines all these properties is a heavy mineral lubricating oil. Other liquids such as water may also be employed; However, the use of heated air or. other gas is not excluded, and because of the cOmparatiVeIyuni'fQrm temperature of the drying evaporative gas of the spinning cabinet, this gas may also be employed, in which case the candles or heating-devices for the spinning solution maybe placed in the exhaust lines of the heated evaporative atmosphere.

f The heating medium may be circulated either by thermosyphonic action or by pumps or fans vfrom'thechamber wherein it heats the spinning solution toanother chamber where it is subjected .to the action of heating elements such as steam coils, electrically heated elements, or by coils containing the hot evaporative atmosphere from the spinning jet, or these heating elements may be 'placed inthe chamber wherein the spinning solution is heated.

'As stated, the temperature to which the spinning solution is elevated just prior to its extrusionthrough the orifices of a spinneret is prefer- Examples oforganic esters wherein ably somewhat below the temperature of the drying evaporative atmosphere at that point; The temperature of the spinning solution in the jet should preferably not be raised above the boiling point of the solvents therein, since under these conditions bubbles may be formed in the filaments issuing from the jet In order further to illustrate my invention reference is had to the accompanying drawing Figure 1 isfa vertical cross section of a spinning unit provided with one form of means for carrying out my invention.

Figure 2 is a vertical cross section of a part of a spinning unit provided with another means for carrying out my invention.

- Figure 3 is a vertical cross section of a part of a spinning unit provided with still another means for carrying out my invention.

Figure 4 is a vertical cross section of a part of a spinning unit having a, restricted evaporative space provided with the means for heating the spinning solution shown in'Figure l. v

Referring to Figure 1', the reference numeral 1 indicates the walls of a dry spinning unit, which walls are preferably lagged with a suitable heat insulating material tov prevent heat loss. While only one spinning unit is shown in the drawing, usually two, three, fouror more are placed together'in one cabinet. The spinning solution is fed by the pipe to a pump 3 which supplies a practically uniform amount of spinning solution per unit of time to the pipe 4 which leads to a candle 5 that contains afiltering medium in order to filter out any trace of solid impurities'that may 11!) be present in the spinning solution. The spinning solution from the candle 5 passes to the metal cap or jet 6 having a number of holes or orifices of required size therein.

Upon extrusion of the spinning solution through the orifices of the jet 6, the fine threads of spinhing solution lose at least part of their volatile solvents as vapors, and assume the form of tough filaments or threads '7 of predetermined size. These filaments pass under the guide roller 8 1.21;

around the rotating roller 9- and pass to any the spinning unit or the gas may be heated by coils in the base of the spinning unit or by steam coils l0 .placed along the walls 1 thereof. If desired, two or all three of these methods of heating the evaporative gas may also be employed. The evaporative gas maybe forced into the base of the spinning unit or it may be drawn up through the same by suction supplied to the exhaust pipe 11 which is preferably supplied with a perforated cap 12.

In the form of my invention shown in Figure 1, the spinning solution pump 3 and connecting pipe 4 are contained in a chamber 15 formed by a the partition 16, while the candle filter 5 is placed in a tightly fitting, tube 17 surrounded by the chamber 18 formed by the partition 19. The chambers 15and 18 may be common to all of the spinning units of the cabinet or these chambers may be interconnected with those of the other spinning units of the cabinet in those cases where more than one spinning unit are employed in a cabinet. Any suitable heating medium as above described may be circulated in the chambers 15 and 18 and the temperatures of these cabinets may be the same or they may be diiferent. If they are different, the temperature of the chamber 18 should preferably be higher than that of the chamber 15. In any event, the temperature of the heating media and the amount of surface of the pump 3, pipe 4, and candle 5 should be such that when the spinning solution leaves the spinning jet 6, it has a temperature that is substantially in equilibrium with the temperature of the drying evaporative atmosphere.

In the form shown in Figure 2, no candle filter is used, the spinning solution being completely filtered prior to its being introduced to the pump 3. In this case a pipe 20 that is screw-threaded at each end replaces the candle 5 of Figure 1, and the spinning solution is caused to attain the desired temperature in the tube 20. The construction of the other parts of the device shown in Figure 2 is otherwise the same as that shown in Figure 1. Often when the boiling point of the solvent employed in the spinning solution is appreciably above room temperature, I prefer not to heat the spinning solution while in the pumps, since this may cause mechanical difficulty. In those cases I use the device shown in Figure 3 wherein the pump 3 is outside of the spinning unit and the spinning solution is previously filtered and then heated. For the heating, I may employ the chamber 25 formed by the partition 26 and the spinning solution passes from the pump 3, pipe 4 to the screw-threaded pipe 27 contained in the chamber 25, which is provided with any suitable heating media as above described.

As described in my copending application No.- 333344 filed herewith, it is desirable to have the cross sectional area of the space wherein the solvent is evaporated from the filaments restricted. In Figure 4 there is shown means for combining the advantages of heating the spinning solution prior to extrusion, through the spinneret with the advantages of employing a restricted evaporating space. In'this figure the means for preheating the spinning solution is precisely that,

as shown in Figure 1, but the evaporativespace is restricted by means of the partitions 30 so that the space through which the heated evaporative atmosphere flows is greatly reduced.

In all or" the forms shown on the drawing it will be seen that the pipe 11' for exhausting the heated evaporative gas passes through the heating chambers 18 or 25. This arrangement provides auxiliary means for heating the heating medium in these chambers, since the exhaust gases passing through this pipell are at a substantially uniform elevated temperature.

As an illustration of a mode of carrying out my invention the following is' given. A spinning solution containing 25 parts by weight of an acetone soluble cellulose acetate is dissolved in parts by weight of a solvent mixture containing 95% of acetone and 5% of water. This solution is fed by the pipe 2, pump 3, pipe 4' perature of the heating media contained in the ture of the spinning solution just prior to the time it issues from the jet is approximately 55 C.

Air is draw'nthrough the spinning unit 1 and the temperature of-the heating coils 10 is such that the temperature of the air is maintained at approximately 60 C. The spinning'solution is fed at such rate and is drawn by the .rotating roller 9 at such rate that a yarn of 150 denier containing 40 filaments is spun at the of the spinning solution is reduced from 55 C.,

as above described, to 50 C., theyarn produced has a duller lustre and has a much flatter cross section.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention what I claim and desire to secure by Letters Patent is:

1. In a device for dry spinning of artificial filaments from solutions of organic derivatives 3 of cellulose in a volatile solvent, the combinagas is adapted to flow, a spinning jet in said spinning'unit, a pump and means for feeding the spinning solution to said jet and means for heating said pump and said feeding means.

2. In a deviceffor dry spinning of artificial filamentsfrom solutions of organic derivatives of cellulose in a volatile solvent, the combination of a spinning unit through which a heating gas is adapted to fiow, a spinningjetin said spinning unit, a heating chamber superposed upon said spinning unit, a pipe for leading the heated gas from the spinning unit through the heating chamber and means contained in said chamber for feeding spinning solution to said spinning jet.

3. In a devicefor dry spinning of artificial filaments from solutionsof organic derivatives of cellulose in a volatile solvent, the combination of a spinning unit through which a heating gas is adapted to flow, a spinning jet insaid spin ning unit, a heating chamber containing a heated 1 tion of a spinning unit through which a heating liquid superposed upon said spinning unit, a pipe 4. Method of forming artificial filamentscomprising'forcing a heated solutionof an organic derivative of cellulose in 95% acetone through a passage surrounded by a relatively large volume a of a heating medium whereby the solution is.

heated and maintained at a uniform temperature of substantially 55 C. and then extruding the same through the orifices of a spinneret into a drying evaporative atmosphere of air drawn through the cell.

l WILLIAM WHITEHEAD. 

